Data processing and word processing terminals typically have displays which differ in desired format. Data processing displays display information in a generally horizontal format of 132 characters wide by approximately 50 lines high while correspondence displays or word processing displays utilize a vertical format of 80 characters wide by 66 lines high.
In some cases the display is capable of having a display pattern on the face of the CRT in either a horizontal or a vertical format but the display configuration is fixed either by a wiring or by substitution of electronic controls. This allows a user to chose the orientation he desires most and then to set up or to configure the display in that orientation or have it configured by the manufacturer. In some cases the displays are rotatable and provide for an altering of the format such that the entire display format is available for the face of the CRT but the dimensions of the characters are altered to permit complete display. For example, the width dimension of a character may be compressed to allow the display of 132 characters even though the CRT is oriented with its short dimension in the horizontal direction.
In this manner the displays are positionable to present a different orientation but they do not provide the uniformity of character appearance normally associated with the display.
The compression of the characters thus forces the entire refresh memory contents into conformity with the dimensional requirements of the CRT face.